This invention deals with pipe, and more particularly with an indexed pipe utilizing marked reference systems for indexing.
Pipes of all sizes and types, such as: Poly Vinyl Chloride, Cast or Ductile Iron, Steel, Clay, or asbestos cement, are currently buried in the ground or totally enclosed and require maintenance. Such pipes are extensively used in the fields of water supply, sewerage, and transmission of other liquids and gases.
Ductile Cast Iron Pipe is commercially available in standard lengths of 18 feet, 3 inches. The pipes, laid end to end, are joined by inserting the plain-end of one length of pipe into the bell-end of another, and buried in the ground at varying depths, depending upon local codes, climatic and other considerations.
When a section of pipe is dug up and exposed for purposes of repairing, installing a service tap, installing a valve, tee or any other fitting, the usual procedure is to cut out the required section of pipe and substitute it with the appropriate replacement. Couplings are used to secure the replacement in position.
Use of two clamps, couplings or collars is unavoidable in the substitution of the replaced section. Such clamps are very expensive and require significant man-hours of skilled labor to install.
Use of two clamps involves extra joints where the piping may separate due to excessive earth movement or unequal settlement, resulting in an emergency situation. In addition, the use of two clamps also means extra joints where leakage may occur, resulting in increased product losses or infiltration of ground water in sanitary sewer systems. In either case, such leaks represent increased monetary costs, in terms of product losses or higher operational costs.
Further, extra skilled labor costs are required in the preparation and installation of two clamps.
By marking the pipe in any accepted system of measurement, such as feet or meters, the economics and savings would be realized, since it would be possible to know the lengths of the various sections of the pipes involved. When the replacement is close to either of the original joints of the pipe, it would be economical to substitute a length of pipe from the replacement to the closer of the two original pipe joints, thereby utilizing only one repair collar or clamp rather than two.
Ordinarily, while making a wet service tap, a small excavation is initially made to reveal the pipe. This excavation is then enlarged to accommodate the workers. The markings on the pipe would indicate the direction in which the excavation should be enlarged to reveal an adjoining pipe-end.
Under certain circumstances, some pipes develop longitudinal cracks if a hole for the service tap in the pipe sidewall is drilled too close to the end of the pipe section. Thus, if the markings on the pipe indicate that the initial excavation is too close to the pipe end, then the excavation would be directed towards the center of the pipe, away from the joint.
In many instances, due to varying soil conditions, water from a damaged pipe joint may not surface at that point. It may travel along the pipe and surface some distance away from the point from which it actually escapes. Normally, an initial excavation is made at the point where the water is surfacing. If the leak is not revealed, the markings on the pipe would indicate the direction in which the excavation should be enlarged to reveal the pipe joint.
Searching for an elusive leak location is, at best, a frustrating and time consuming operation, and especially so when working conditions are unfavorable. Maintenance personnel need as much help as possible to eliminate probable problem points quickly and effectively before proceeding with further investigations. Indexed pipe would eliminate uncertainty about the location of each adjoining joint, facilitate the decision making process, increase productivity and reduce losses and downtime.
Significant savings would be realized if individual sections of buried or concealed piping systems were indexed to reveal the location of original joints within the piping system by exposing any portion of the pipe. The indexing provides a viable and vital option to the maintenance personnel by aiding in evaluating various maintenance alternatives quickly and allowing maintenance personnel to adopt the most economical approach. The indexing helps in conserving vital resources and contributes to the enhancement of overall system efficiency.